Neisseria meningitidis, is an encapsulated bacterium classified into different serogroups based on the chemical composition and immunologic features of the capsular polysaccharide (CP; 1). Human isolates are almost totally accounted for by 5 serogroups (A, B, C, Y and W135). No vaccine is generally available for the prevention of infections caused by serotype B strains, which often account for more that half of meningococcal disease cases in developed countries (2). Major obstacles to the development of capsule-based vaccines are the poor immunogenicity of the group B capsular polysaccharide (MenB CP) even after protein conjugation, and concerns over the induction of autoantibodies (3). These features are probably related to the structural identity between the Neisseria meningitidis group B capsular polysaccharide and human polysialic acid (PSA), both consisting of alpha 2-8 linked N-acetyl neuraminic acid. It is readily apparent that the production of a safe and effective vaccine against MenB would be particularly desirable. Studies using mAbs have defined two different classes of capsular epitopes naturally present on the meningococcal surface (4, 5, 6). One class is cross-reactive with human PSA, while the other is non-cross reactive and protective.
Therefore it is an object of the invention to provide further and improved immunogenic compositions for providing immunity against Neisseria meningitidis. It is a further object of the invention to provide peptides that mimic the antigenic features of capsular epitopes naturally present on the meningococcal surface which are both non-cross reactive and protective.